Title page for ETD etd-02232005-181427

Computer-Aided Diagnosis Tool for the Detection of Cancerous Nodules in X-Ray Images

Degree

Master of Science in Electrical Engineering (M.S.E.E.)

Department

Electrical & Computer Engineering

Advisory Committee

Advisor Name

Title

Jerry Trahan

Committee Chair

Bahadir K. Gunturk

Committee Member

Hsiao-Chun Wu

Committee Member

Keywords

roc analysis

artificial neural networks

medical imaging

Date of Defense

2005-01-14

Availability

unrestricted

Abstract

This thesis involves development of a computer-aided diagnosis (CAD) tool for the detection of cancerous nodules in X-ray images. Both cancerous and non-cancerous regions appear with little distinction on an X-ray image. For accurate detection of cancerous nodules, we need to differentiate the cancerous nodules from the non-cancerous. We developed an artificial neural network to differentiate them. Artificial neural networks (ANN) find a large application in the area of medical imaging. They work in a manner rather similar to the brain and have good decision making criteria when trained appropriately. We trained the neural network by the backpropagation algorithm and tested it with different images from a database of thoracic radiographs (chest X-rays) of dogs from the LSU Veterinary Medical Center.

If we give X-ray images directly as input to the ANN, it incurs substantial complexity and training time for the network to process the images. A pre-processing stage involving some image enhancement techniques helps to solve the problem to a certain extent. The CAD tool developed in this thesis works in two stages. We pre-process the digitized images (by contrast enhancement, thresholding, filtering, and blob analysis) obtained after scanning the X-rays and then separate the suspected nodule areas (SNA) from the image by a segmentation process. We then input enhanced SNAs to the backpropagation-trained ANN. When given these enhanced SNAs, the neural network recognition accuracy, compared to unprocessed images as inputs, improved from 70% to 83.33%.